1. Field of the Invention
Exemplary embodiments of the present disclosure may relate to a polarization conversion apparatus configured to convert unpolarized light to polarization.
2. Description of Related Art
Projection optical systems including projectors and projection systems using an LCD (Liquid Crystal Display) panel and an LCOS (Liquid-Crystal-On-Silicon) micro display require polarized light due to an operational principle of LCD panel and LCOS micro-display itself.
Due to the fact that the general light source produces un-polarized light, the projection optical systems such as projectors and projection systems using an LCD panel and an LCOS micro-display need an optical device capable of producing polarized light. As one of simple methods producing the polarized light from these light sources, there is provided a method of using a polarization plate. However, it should be noted that, although the polarization having passed the polarization plate can be used, the polarization perpendicular to the transmittive polarization is absorbed or lost due to reflection. Therefore, this type of method generates a 50% light loss.
As a result, attempts have been made to overcome these disadvantages by developing polarization conversion devices capable of re-using the polarization that is wasted in the projection optical systems using the LCD panel and LCOS micro-display. Therefore, so-called polarization conversion apparatus can be used to overcome efficiency losses that would otherwise arise from the use of un-polarized light sources in systems requiring polarized illumination.